Take a typical cross-section of rockfill embankment slope in Yaan-Luku highway as the research object, reliability analysis is studied under the condition of water table of 840.85m, 851.50m, and loading condition of natural state and horizontal seismic acceleration of 0.2g, respectively. Raw data use Kolmogorov-Smirnov test (K-S test) to determine the distribution type of parametric variation. And the parameters were sampling with Latin hypercube sampling (LHS) method and Monte Carlo (MC) method, respectively, to obtain state function and determine safety factors and reliability indexes. A conclusion is drawn that the times of simulation based on LHS method were less than Monte Carlo method. Also the convergence of failure probability is better than the Monte Carlo method. The safety factor is greater than one and the failure probability has reached to 35.45% in condition of earthquake, which indicating that the instability of rockfill embankment slope is still possible.

At present, due to various reasons, cannot do a large number of field measurements, and the measured results often can only reflect the local stress field distribution. What’s more, the measured results has discreteness, it’s difficult to describe the law of the initial stress field distribution in the entire region. This paper combines topographic and geological conditions and the measured in-situ stress value of Jinping I hydropower station dam area, using FLAC3D4.0, select geological section profile of II1 exploration line for reference, to simulate the incised process of the valley. We get the stress field distribution when rock gravity acting alone, and exert horizontal tectonic stress based on the calculate result of gravity field in the VI terrace model. We inversion the distribution of current Valley stress field, and validate the rationality of the design after compare with the measured data. We obtain the features of stress field of current valley. And we also proved that the regional principal compressive stress plays a decisive role in the formation of the current valley stress field.

The Hangu research area is belonged to the typical inshore soft soil area. The engineering geological properties of soil in the research area is rather poor. With the rapid development of Tianjin and the improvement of people’s living standards, with the increasing demand of people’s lives of with water and industrial water, a lot of groundwater exploited caused groundwater elevation changes and resulted in pore water pressure changes and leaded to effective stress changes of soil, which eventually caused land subsidence . Numerical analysis method is used to this paper to research land subsidence of Hangu,Tianjin.